Reexamining the Returns to Training
研究工资方程中正式培训的函数形式，发现立方根拟合最佳，并利用半非参数估计得出培训回报率为150-180%，调整异质性后降至40-50%，且回报存在异质性。
Abstract We investigate the functional form for formal training in a wage equation and derive estimates of its rate of return. The cube root fits best in our two data sets. We show that if wages are not adjusted continuously, estimating the return to training requires one lag and one lead of training. Using the cube root and a semi-nonparametric estimator, estimated returns are 150–180 percent. Adjusting for heterogeneity in wage growth, promotions, and direct costs reduces the return to 40–50 percent. We find evidence of heterogeneity in returns. Our estimates can thus be regarded as the return to training for the trained, but cannot be extrapolated to the untrained.